Perhaps the original photo can be accessed via https://photos.app.goo.gl/MkMW5RS5e6rND5Tb6 or, if not, then via https://photos.app.goo.gl/gzqA7M7bhitUzdo77 That said, I took a look at the EXIF and indeed, there is no location data in the photo file, at least not once downloaded and perhaps not as shared. Yet when the image is viewed in the Google Photos app on the phone, a map is displayed with the correct location of the observation. So that is a mystery to me, but this is not an iNaturalist problem to be solved, this appears to be a Google Photos issue of some sort.
When adding an observation from a photo on the phone’s SD card using the iNaturalist app, if he navigates to the Google Photo menu item and pulls the photo in that way, the location data is stripped out. If he uses a file manager menu item to locate the image, the location data is picked up by iNaturalist. The catch is that the file manager takes a long time to load the images. The file manager is apparently loading the full resolution image. Google Photos loads images much more quickly, apparently using a thumbnail capability to rapidly display the image.
The upshot is that this problem is solved in the sense that one must load the image directly via a file manager and not via the Google Photos interface to the photos even when working from within the app. Thanks for the assistance, I can only hope that this information might also help Ian as well!